Refrigerating system.



E.- CARPENTER. REFRIGERATING SYSTEM.

APPLIGATION FILED 1130.2, 1907.

UNITED sTATEs APATENT oEEIcE.

EUGENE CARPENTER, 0F NEWTON, MASSACHUSETTS.

` REFRIGERATING SYSTEM.

Specification of Letters Patent.

Patented Jan. 18, 1910.

Application iled December 2, 1907. Serial No. 404,672.

The present invention relates to a refrig` erating system and is embodied in a combination with such a system of a controlling device arranged to respond directly to an increase of pressure in the refrigerating pipes in addition to the controlling device now commonly .employed which responds to changes of temperature in the chamber.

which is cooled by the system. i

The purpose ot' the invention is to take care of the excess pressure in the refrigerating pipes in cases where the temperature to be maintained in the chamber which is being cooled is considerably above the freezing point. The device is mainly intended for use in cases where the temperature which is to be maintained by the cooling device is 50 Iiahrenheit, or over, so that the expanding gases in the cooling pipes contain a pressure which it is difficult to confine in the piping system, thereby causing leakage. This high. pressure will be produced before the temperature of the chamber which is being cooled increases to a degree suicient to control the compressing apparatus through the agency of a thermostat, and in accordance with the present invention a secondary controlling device operated directly by the pressure iu the refrigerating pipes is employed to start the condensing pump from time to time and keep the pressure down to a degree which can be handled withsafety.

The invention is herein shown as embodied in a refrigerating system in which the compressing apparatus is controlled by an electric switch, the operation of which in turn is uorlnally controlled by the action of a thermostat so arranged as to close the switch and set the compressing apparatus in operation when the temperature of the chamber being cooled rises to a certain point. In accordance with the invention, a secondary circuit controller is employed which is arranged to be operated by pressure of the gases in the system so as to start the compressing apparatus when said pressure rises beyond a certain point regardless of the temperature of the chamber which is being cooled.

The drawing is a diagram of the system embodying the invention, the regulating device which forms the main feature of the in'- vent-ion being shown on an enlarged scale and in section.

The system in which the invention is embodied consists, as usual, of the compressing pump A, condenser'coil B, the expansion valve C and the refrigerating coils D which are within the chamber D2 from which the heat is to be extracted to maintain the temperature at a given point. In the construction shown, the compressor' lump A is arranged to be driven by an e ectromotor A2, the circuit through the motor being controlled by a bi-polar switch a which is underthe control of a solenoid a2. The switch a is so arranged as to be closed when the solenoid is fully energized, there being a continuous circuit through the said solenoid a2 and a resistance a3 which carries current enough to maintain the switch closed but not enough to close the switch when open. The circuit through the solenoid is primarily controlled by means of a thermostat b in the chamber D2, the said thermostat being herein conveniently shown as a member adapted to ybe moved through the agency of temperature changes from a contact b2 to a contact Z13. In the posit-ion shown, the apparatus is at rest, and in order to start the same the member b is moved through a change in temperature, or otherwise, from its engagement with the kcontact b2 into engagement with the contact b3."

This closes a circuit from the source of current E through the conductor l, the solenoid a2, conductor 2, thermostat b, contact b3, conductor 3, a portion of the resistance a3 and conductor 4 to the return conductor 10 and other side of the source E. This short to be maintained in the chamber D2 is rela- I 03 being that which stops the o eration of circuits a portion of the resistance a3 so that the solenoid a2 becomes energized to a suicient degree to close the switch a, so as to start the compressing pump A. As the temperature in the chamber D2 falls, the member b will leave its engagement with the contact b3, but the pump A will continue to run owing to the fact that suilicient current flows through the solenoid a2 and the resistance an3 to keep the switch closed. When, however, the temperature has decreased to the desired point, a circuit will be closed through conductor 1, conductor 5, switch member 0, conductor 6, contact b2, thermostat b, conductor 2, and thence through the resistance a3 and conductor` 4 to-the conductor 10, thus short circuitmg the solenoid and permitting the switch a to open.

In cases where the temperature which 1s tively high, the gases in the refrigerating coils D expand t'o a high pressure before the temperature in the chamber D2 is aected suiiciently to control the apparatus through the agency of the thermostat b. It is desirable, therefore, to j, provide means for keeping this pressure reduced by causing an operation of the compressing pump A whenever the pressure has reached a point beyond which it is dangerous or undesirable to go. For this purpose, a supplemental controlling device is employed which is directly under the control of the pressure in the coil D, the controlling device being herein shown as the switch member c, previously referred to, which switch member is arranged to be operatedcby means of a movable abutment or diaphragm d in a chamber d2 which receives the pressure in the coil D through a pipe cl3. The diaphragm d is connected through a lever e with the switch member c, the said switch member thus being longitudinally movable in guides 02 between two sets of contacts c3 and 030Ev and c4 and 040, the normal-position of the switch member c being that shown in the drawing, the circuit which is then closed by said switch through the contacts c3 and the compressing pump A, when t e thermostat b is in the position also shown in the drawing. Assumin however, that the pressure in the coil exceeds a given point without yan increase in temperature in the chamber D2 suiicient to start the pump A through the action of the thermostat b, it will be seen that such pressure being admitted to the chamber d2 willact upon the diaphragm d, and through the agency of the lever e will close a circuit through the contacts c4 and 0*". This circuit is through the conductor 1, the solenoid a?, conductor 2, conductor 20, contact c4, switch member c,

contact 04, conductor 7, conductors 3, 4 and 10, so that the current flowing lover said V circuit will energize the solenoid and start the compressor. The operation of the compressor will then continue until the pres.- sure is suiiiciently reduced to permit the o eration of the switch member c through t e agency of the spring f which will then restore the parts to the position shown, in which they are entirely `under the control of the thermostat b.

While any form of pressure actuated device may be employed to control the circuit, the device herein shown consists of a dia* phragm d clamped or otherwise secured between two members d4 and d5, the lower member' forming, in conjunction with the diaphragm, the compression chamber into which the pipe d3 leads, while the upper member constitutes a guide for an actuator e2 which is connected with the lever e pivotally supported at e3. The spring f which is provided with an adjusting ollowerl f2 bears on top of the member e? in order to hold the parts in the normal position shown. By this construction, the actuator e2 is entirely outside of the pressure chamber d2, and being held in contact with the diaphragm @l by means of the spring f, requires no fastening devices, so that the diaphragm can be solid and unperforated. Furthermore, all the external connections are outside of the diaphragm chamber so that no stuiing boxes are -required and there is no danger of leakage from the chamber. The upper member d4 of the diaphra m support is furthermore shaped so as to a ord a solid abutment for the diaphragm when subjected to pressure so that a very thin and sensitive diaphragm can be employed without danger of breakage or leakage.

While the construction hereinbefore described constitutes a practical embodiment of the invention, it is not intended to limit the invention to the specific construction and arrangement of the several instrumentalities employed to attain the desired result, since modiications may obviously be made Without departing from the invention.

Claim.

In a refrigerating system, a compressor; an electro-motor to operate said compressor; a source of current to operate said motor; a switch to control a circuit leading from said source of current through said motor; a solenoid and resistance .in series with a permanently closed circuit from said source of current, said solenoid fcontrolling the operation of said switch; a shunt circuit around the solenoid including the whole of independent of the thermostatic switch, and In testimony whereof, I have signed my adapted to open the first shunt circuit and name to this speclication in the presence of close the second shunt circuit in response two subscribing Witnesses.

to an increase in pressure; and a diaphragm A EUGENE CARPENTER. subjectedto the pressure of the gas in the Witnesses: refrgerating coils to operate said pressure JAS. J. MALONEY,

operated switch. W. E. COVENEY. 

